Sunday, May 20, 2018

Overcast with Haze, 72 °F

Science-Cafe-Quantum Dot

The fluorescent color of a quantum dot can be seen under a ultra-violet light and varies depending on size

Photo courtesy of: Office of Research Communications


The Pulse Laser System in Van Patten’s lab is used to measure the speed at which it takes two charges to separate in a quantum dot, important in solar energy conversion

Photo courtesy of: Office of Research Communications

Featured Stories

Professor to present quantum dots as wave of the future

Finding a treatment for cancer. Solving our energy crisis. Creating high security encryption codes. A tiny nanoparticle may not be able to remedy all the world's biggest problems. But it may soon be the answer to a few of them.

Gregory Van Patten
, a professor in the Department of Chemistry and Biochemistry, has been researching quantum dots since 2005, originally just as a sideline project.

Speaking at Ohio University's next Science Café discussion at 5 p.m. Wednesday, Feb. 8, in the Baker University Center Front Room, Van Patten will explain how these small particles have become a big deal.

"Within two to three years it is likely that we will see this product on the market," says Van Patten, referring to fluorescent semiconductor nanocrystals called quantum dots.

But how does one envision something the size of a nanometer, 10-9 meters? Imagine a meter stick expanding to match the diameter of the earth. On such a scale, a nanometer would be equal to about the size of a marble. Quantum dots range in diameter, with some as small as golf balls, others as large as softballs on this hypothetic scale, explains Van Patten.

Typically made out of semiconducting materials such as silicon and gallium arsenide, quantum dots are so small that their behavior cannot be understood according to the everyday traditional physics we normally experience, says Van Patten.

Instead scientists model the quantum dots' physical properties on the movement of their electrons. Just as the sound (frequency) of a guitar string is especially sensitive to the space between your hand placement and the bridge, the characteristics of quantum dots are highly affected by the distance their electrons have to move within the dot.

"There is a new physics that takes over at small sizes," says Van Patten, "it's called Quantum Mechanics." And with this "new physics", nanoscale semiconductors can replace the traditional combination of semiconductors, insulators, and metals used to create current electronics.

Instead of requiring several materials with different properties, we can use a single type of material whose function can be altered with size.

Today, quantum dot research is no longer taking a back seat for scientists such as Van Patten or researchers throughout the country. This May, faculty including Department of Physics and Astronomy Professor, Sergio Ulloa, and students from Ohio University will be attending the seventh biannual International Conference on Quantum Dots, which will be held for the first time in the United States.

With their capacity to change color and absorb heat depending on their size, quantum dots have the capability to play a role in biomedical-imaging and hyperthermia treatment of cancerous cells, notes Department of Physics & Astronomy Assistant Professor Eric Stinaff whose own quantum dot research includes quantum dot

"There is a lot of interest in this field," says Stinaff, "but a lot of people need funding."

And while Stinaff believes Ohio University is in very good standing, in terms of research, talent, and funding, nationally the quantum dot's greatest hurtle may not be scientific, but financial.

Specifically interested in quantum dot's implications for solar energy conversion, Van Patten reiterates the concern of national funding, or more accurately, lack thereof, when it comes to our country's budget for improving energy technology.

But from lighting to digital display to energy to biomedicine to quantum computers, these nanoparticles have huge potential as Van Patten's "The Big Deal about Small Stuff" Science Café Discussion will emphasize.

In the future, quantum dots will be a part of our everyday life, in products as far ranging as cosmetics to electronics. "By the time our undergraduate students are 40, they will see these products at Walmart and say 'I heard about that at the Science Café,'" predicts Ulloa.